EDIT: I have probably made a mistake in this post. rsync is not really a good way to make a speed measurement on files of this size.
I am not really trying to get an answer here, but I am posting out of curiosity and possibly to the benefit of others who want to know about the speeds that LinkStation Duo can achieve.
Below is a sampling of my transfer speeds when using rsync (locally, on my machine with LinkStation mounted through AFP). I am running at the default MTU, through wired network over one of the Buffalo routers. The copy goes from a USB drive. The files usually are somewhere between 5 and 10 MB. Does this look like the speeds that others are getting?
img_4723.cr2 9006783 100% 26.74MB/s 0:00:00 (xfer#1568, to-check=1609/3223)img_4724.cr2 8982912 100% 6.31MB/s 0:00:01 (xfer#1569, to-check=1608/3223)img_4725.cr2 9154486 100% 6.79MB/s 0:00:01 (xfer#1570, to-check=1607/3223)img_4726.cr2 8871693 100% 4.90MB/s 0:00:01 (xfer#1571, to-check=1606/3223)img_4727.cr2 8950476 100% 22.68MB/s 0:00:00 (xfer#1572, to-check=1605/3223)img_4728.cr2 10594134 100% 5.93MB/s 0:00:01 (xfer#1573, to-check=1604/3223)img_4729.cr2 8667837 100% 16.37MB/s 0:00:00 (xfer#1574, to-check=1603/3223)img_4730.cr2 8714528 100% 5.68MB/s 0:00:01 (xfer#1575, to-check=1602/3223)img_4732.cr2 9724357 100% 4.32MB/s 0:00:02 (xfer#1576, to-check=1601/3223)img_4733.cr2 9250251 100% 5.38MB/s 0:00:01 (xfer#1577, to-check=1600/3223)img_4734.cr2 9764205 100% 6.33MB/s 0:00:01 (xfer#1578, to-check=1599/3223)img_4735.cr2 8869135 100% 6.14MB/s 0:00:01 (xfer#1579, to-check=1598/3223)img_4736.cr2 8926171 100% 29.97MB/s 0:00:00 (xfer#1580, to-check=1597/3223)img_4737.cr2 9320876 100% 6.91MB/s 0:00:01 (xfer#1581, to-check=1596/3223)img_4738.cr2 9144171 100% 6.42MB/s 0:00:01 (xfer#1582, to-check=1595/3223)img_4739.cr2 9434730 100% 27.76MB/s 0:00:00 (xfer#1583, to-check=1594/3223)img_4740.cr2 9075237 100% 8.29MB/s 0:00:01 (xfer#1584, to-check=1593/3223)img_4741.cr2 10184325 100% 7.97MB/s 0:00:01 (xfer#1585, to-check=1592/3223)img_4742.cr2 10754902 100% 29.73MB/s 0:00:00 (xfer#1586, to-check=1591/3223)img_4743.cr2 9315185 100% 24.94MB/s 0:00:00 (xfer#1587, to-check=1590/3223)img_4744.cr2 11817822 100% 25.90MB/s 0:00:00 (xfer#1588, to-check=1589/3223)img_4745.cr2 11290305 100% 13.84MB/s 0:00:00 (xfer#1589, to-check=1588/3223)img_4746.cr2 10391357 100% 10.70MB/s 0:00:00 (xfer#1590, to-check=1587/3223)img_4747.cr2 9088720 100% 31.29MB/s 0:00:00 (xfer#1591, to-check=1586/3223)img_4748.cr2 9016195 100% 5.21MB/s 0:00:01 (xfer#1592, to-check=1585/3223)img_4749.cr2 9229784 100% 18.16MB/s 0:00:00 (xfer#1593, to-check=1584/3223)img_4750.cr2 8971504 100% 28.61MB/s 0:00:00 (xfer#1594, to-check=1583/3223)img_4751.cr2 13581698 100% 7.33MB/s 0:00:01 (xfer#1595, to-check=1582/3223)img_4752.cr2 9754923 100% 6.02MB/s 0:00:01 (xfer#1596, to-check=1581/3223)img_4753.cr2 10419446 100% 7.62MB/s 0:00:01 (xfer#1597, to-check=1580/3223)img_4754.cr2 9695155 100% 5.97MB/s 0:00:01 (xfer#1598, to-check=1579/3223)img_4755.cr2 8926573 100% 25.02MB/s 0:00:00 (xfer#1599, to-check=1578/3223)img_4782.cr2 8749595 100% 21.88MB/s 0:00:00 (xfer#1624, to-check=1553/3223)img_4783.cr2 8843028 100% 2.19MB/s 0:00:03 (xfer#1625, to-check=1552/3223)img_4784.cr2 8716708 100% 4.59MB/s 0:00:01 (xfer#1626, to-check=1551/3223)img_4785.cr2 8774068 100% 29.05MB/s 0:00:00 (xfer#1627, to-check=1550/3223)img_4786.cr2 8762624 100% 8.34MB/s 0:00:01 (xfer#1628, to-check=1549/3223)img_4787.cr2 9109889 100% 7.20MB/s 0:00:01 (xfer#1629, to-check=1548/3223)img_4788.cr2 9107869 100% 6.92MB/s 0:00:01 (xfer#1630, to-check=1547/3223)img_4789.cr2 9906201 100% 25.94MB/s 0:00:00 (xfer#1631, to-check=1546/3223)img_4790.cr2 9389714 100% 2.67MB/s 0:00:03 (xfer#1632, to-check=1545/3223)img_4791.cr2 9824802 100% 4.12MB/s 0:00:02 (xfer#1633, to-check=1544/3223)img_4792.cr2 9268240 100% 30.37MB/s 0:00:00 (xfer#1634, to-check=1543/3223)img_4793.cr2 9916116 100% 25.00MB/s 0:00:00 (xfer#1635, to-check=1542/3223)img_4794.cr2 10092534 100% 6.19MB/s 0:00:01 (xfer#1636, to-check=1541/3223)img_4795.cr2 10018324 100% 5.01MB/s 0:00:01 (xfer#1637, to-check=1540/3223)img_4796.cr2 9063142 100% 26.02MB/s 0:00:00 (xfer#1638, to-check=1539/3223)img_4797.cr2 9236930 100% 5.00MB/s 0:00:01 (xfer#1639, to-check=1538/3223)img_4798.cr2 10473454 100% 19.45MB/s 0:00:00 (xfer#1640, to-check=1537/3223)img_4799.cr2 9479846 100% 6.34MB/s 0:00:01 (xfer#1641, to-check=1536/3223)img_4800.cr2 10071371 100% 7.78MB/s 0:00:01 (xfer#1642, to-check=1535/3223)img_4801.cr2 10169637 100% 7.46MB/s 0:00:01 (xfer#1643, to-check=1534/3223)img_4802.cr2 10009656 100% 15.01MB/s 0:00:00 (xfer#1644, to-check=1533/3223)img_4803.cr2 10177767 100% 10.61MB/s 0:00:00 (xfer#1645, to-check=1532/3223)img_4804.cr2 9677441 100% 20.76MB/s 0:00:00 (xfer#1646, to-check=1531/3223)img_4805.cr2 10160250 100% 26.98MB/s 0:00:00 (xfer#1647, to-check=1530/3223)img_4806.cr2 9537832 100% 5.91MB/s 0:00:01 (xfer#1648, to-check=1529/3223)img_4807.cr2 9023219 100% 29.98MB/s 0:00:00 (xfer#1649, to-check=1528/3223)